Mobile technology is taking over the consumer product fast lane and packaging requirements are becoming more complex and demanding. To meet this demand, the package requires better electrical and thermal performance with higher numbers of input/output terminals. With shrinking electronic devices, such as cell phones, global positioning systems, and hand held computers the integrated circuit packaging must evolve to meet the application requirements. In order to maximize the number of input/output terminal pads, certain requirement on lead spacing and tie-bar location and design have limited the ability to increase the number of terminal pads.
Leadframe types of semiconductor packages are well known and widely used in the electronics industry to house, mount, and interconnect a variety of ICs. A conventional leadframe is typically die-stamped from a sheet of flat-stock metal, and includes a plurality of metal leads temporarily held together in a planar arrangement about a central region during package manufacture by a rectangular frame comprising a plurality of expendable “dam-bars.” A mounting pad for a semiconductor die is supported in the central region by “tie-bars” that attach to the frame. The leads extend from a first end integral with the frame to an opposite second end adjacent to, but spaced apart from, the die pad.
During package manufacture, an IC die is attached to the die pad. Wire-bonding pads on the die are then connected to selected ones of the inner ends of the leads by fine, conductive bond wires to convey power, ground, and signals between the die and the leads.
A protective body of an epoxy resin is molded over the assembly to enclose and seal the die, the inner ends of the leads, and the wire bonds against harmful environmental elements. The rectangular frame and the outer ends of the leads are left exposed outside of the body, and after molding, the frame is cut away from the leads and discarded, and the outer ends of the leads are appropriately formed for interconnection of the package with other, associated components.
In a variant of the above configuration, viz., a “land grid array” (“LGA”), a “quad flat no-lead” (“QFN”), or a “leadless chip carrier” (“LCC”) package, the outer portions of the leads are removed entirely from the package, and a terminal pad, or “land,” is provided on the lower surface of the leads and exposed through the lower surface of the body for mounting and inter-connection of the package to a PCB. In yet another variation, the die pad is “down-set ” relative to the plane of the leads such that its lower surface is exposed through the lower surface of the body for enhanced dissipation of heat from the die.
The demand for higher terminal pad count has stressed this manufacturing process to its practical limit. In order to meet the demand for more input/output terminal pads, a new approach must be developed. The continued evolution of mobile devices and their convergence will continue to pressure the package designs to decrease in size while increasing the number of terminal pads.
Thus, a need still remains for an integrated circuit leadless package system. In view of the continuing pressure to increase the input/output terminal pad count and decrease package size, it is increasingly critical that answers be found to these problems. In view of the ever-increasing need to save costs and improve efficiencies, it is more and more critical that answers be found to these problems. Solutions to these problems have been long sought but prior developments have not taught or suggested any solutions and, thus, solutions to these problems have long eluded those skilled in the art.